Enhanced non-linear interference cancellation (NLIC) operation

ABSTRACT

Aspects of the present disclosure provide techniques and apparatus for wireless communication. In one aspect, a method is provided which may be performed by a wireless device such as a user equipment (UE). The method generally includes: receiving signaling on a plurality of carriers, and dynamically assigning non-linear interference cancellation (NLIC) to a subset of the plurality of carriers based on at least one criteria, wherein the NLIC is available to a number of carriers that is less than a total number of carriers in the plurality of carriers.

BACKGROUND Field of the Disclosure

Certain aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, to enhanced non-linearinterference cancellation (NLIC) operation.

Description of Related Art

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so on. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, 3rd Generation PartnershipProject (3GPP) Long Term Evolution (LTE)/LTE-Advanced (LTE-A) systemsand orthogonal frequency division multiple access (OFDMA) systems.

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations (BSs) viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the BSs to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the BSs. This communication link may beestablished via a single-input single-output, multiple-inputsingle-output or a multiple-input multiple-output (MIMO) system.

A wireless communication network may include a number of BSs that cansupport communication for a number of wireless devices. Wireless devicesmay include user equipments (UEs). Machine type communications (MTC) mayrefer to communication involving at least one remote device on at leastone end of the communication and may include forms of data communicationwhich involve one or more entities that do not necessarily need humaninteraction. MTC UEs may include UEs that are capable of MTCcommunications with MTC servers and/or other MTC devices through PublicLand Mobile Networks (PLMN), for example. Wireless devices may includeInternet-of-Things (IoT) devices (e.g., narrowband IoT (NB-IoT)devices). IoT may refer to a network of physical objects, devices, or“things”. IoT devices may be embedded with, for example, electronics,software, or sensors and may have network connectivity, which enablethese devices to collect and exchange data.

Some next generation, NR, or 5G networks may include a number of basestations, each simultaneously supporting communication for multiplecommunication devices, such as UEs. In LTE or LTE-A network, a set ofone or more BSs may define an e NodeB (eNB). In other examples (e.g., ina next generation or 5G network), a wireless multiple accesscommunication system may include a number of distributed units (e.g.,edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads(SRHs), transmission reception points (TRPs), etc.) in communicationwith a number of central units (e.g., CU, central nodes (CNs), accessnode controllers (ANCs), etc.), where a set of one or more distributedunits (DUs), in communication with a CU, may define an access node(e.g., AN, a new radio base station (NR BS), a NR NB, a network node, agNB, a 5G BS, an access point (AP), etc.). A BS or DU may communicatewith a set of UEs on downlink channels (e.g., for transmissions from aBS or to a UE) and uplink channels (e.g., for transmissions from a UE toa BS or DU).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. NR (e.g., 5G radio access) is anexample of an emerging telecommunication standard. NR is a set ofenhancements to the LTE mobile standard promulgated by 3GPP. NR isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingOFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink(UL) as well as support beamforming, MIMO antenna technology, andcarrier aggregation.

However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in LTE, MTC, IoT,and NR (new radio) technology. Preferably, these improvements should beapplicable to other multi-access technologies and the telecommunicationstandards that employ these technologies.

SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “DETAILED DESCRIPTION” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects of the present disclosure generally relate to NLICarbitration techniques.

Certain aspects of the present disclosure provide a method forinterference mitigation, performed by a wireless device, such as a userequipment (UE), supporting a plurality of carriers. The method generallyincludes: receiving signaling on the plurality of carriers, anddynamically assigning non-linear interference cancellation (NLIC) to asubset of the plurality of carriers based on at least one criteria,wherein the NLIC is available to a number of carriers that is less thana total number of carriers in the plurality of carriers.

Certain aspects of the present disclosure provide an apparatus forinterference mitigation. The apparatus generally includes at least oneprocessor configured to: receive signaling on a plurality of carriers,and dynamically assign non-linear interference cancellation (NLIC) to asubset of the plurality of carriers based on at least one criteria,wherein the NLIC is available to a number of carriers that is less thana total number of carriers in the plurality of carriers, and a memorycoupled to the at least one processor.

Certain aspects of the present disclosure provide an apparatus forinterference mitigation. The apparatus generally includes: means forreceiving signaling on a plurality of carriers, and means fordynamically assigning non-linear interference cancellation (NLIC) to asubset of the plurality of carriers based on at least one criteria,wherein the NLIC is available to a number of carriers that is less thana total number of carriers in the plurality of carriers.

Certain aspects of the present disclosure provide a computer-readablemedium. The computer-readable medium generally includes code, which whenexecuted by at least one processor, causes the at least one processorto: receive signaling on a plurality of carriers, and dynamically assignnon-linear interference cancellation (NLIC) to a subset of the pluralityof carriers based on at least one criteria, wherein the NLIC isavailable to a number of carriers that is less than a total number ofcarriers in the plurality of carriers.

Numerous other aspects are provided including methods, apparatus,systems, computer program products, computer-readable medium, andprocessing systems. To the accomplishment of the foregoing and relatedends, the one or more aspects comprise the features hereinafter fullydescribed and particularly pointed out in the claims. The followingdescription and the annexed drawings set forth in detail certainillustrative features of the one or more aspects. These features areindicative, however, of but a few of the various ways in which theprinciples of various aspects may be employed, and this description isintended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 is a block diagram conceptually illustrating an example of awireless communication network, in accordance with certain aspects ofthe present disclosure.

FIG. 2 shows a block diagram conceptually illustrating an example of abase station (BS) in communication with a user equipment (UE) in awireless communications network, in accordance with certain aspects ofthe present disclosure.

FIG. 3 is a block diagram conceptually illustrating an example of aframe structure in a wireless communications network, in accordance withcertain aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating two exemplarysubframe formats with the normal cyclic prefix, in accordance withcertain aspects of the present disclosure.

FIG. 5 illustrates an exemplary subframe configuration forenhanced/evolved machine type communications (eMTC), in accordance withcertain aspects of the present disclosure.

FIG. 6 illustrates an example deployment of narrowbandInternet-of-Things (NB-IoT), in accordance with certain aspects of thepresent disclosure.

FIG. 7 illustrates an example logical architecture of a distributedradio access network (RAN), in accordance with certain aspects of thepresent disclosure.

FIG. 8 illustrates an example physical architecture of a distributedRAN, in accordance with certain aspects of the present disclosure.

FIG. 9 is a diagram illustrating an example of a downlink (DL)-centricsubframe, in accordance with certain aspects of the present disclosure.

FIG. 10 is a diagram illustrating an example of an uplink (UL)-centricsubframe, in accordance with certain aspects of the present disclosure.

FIG. 11 is a diagram illustrating an example NLIC assignment scenario,in accordance with certain aspects of the present disclosure.

FIG. 12 is a flow diagram illustrating example NLIC operations, inaccordance with certain aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide techniques for CE level andtransmit power determination for UEs in extended coverage. Thetechniques described herein may be used for various wirelesscommunication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asuniversal terrestrial radio access (UTRA), cdma2000, etc. UTRA includeswideband CDMA (WCDMA), time division synchronous CDMA (TD-SCDMA), andother variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856standards. A TDMA network may implement a radio technology such asglobal system for mobile communications (GSM). An OFDMA network mayimplement a radio technology such as evolved UTRA (E-UTRA), ultra mobilebroadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,Flash-OFDM®, etc. UTRA and E-UTRA are part of universal mobiletelecommunication system (UMTS). 3GPP Long Term Evolution (LTE) andLTE-Advanced (LTE-A), in both frequency division duplex (FDD) and timedivision duplex (TDD), are new releases of UMTS that use E-UTRA, whichemploys OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA,UMTS, LTE, LTE-A and GSM are described in documents from an organizationnamed “3rd Generation Partnership Project” (3GPP). cdma2000 and UMB aredescribed in documents from an organization named “3rd GenerationPartnership Project 2” (3GPP2). NR (e.g., 5G radio access) is an exampleof an emerging telecommunication standard. NR is a set of enhancementsto the LTE mobile standard promulgated by 3GPP. The techniques describedherein may be used for the wireless networks and radio technologiesmentioned above as well as other wireless networks and radiotechnologies. For clarity, certain aspects of the techniques aredescribed below for LTE/LTE-Advanced, and LTE/LTE-Advanced (LTE-A)terminology is used in much of the description below. LTE and LTE-A arereferred to generally as LTE. Depending on the context, “channel” mayrefer to the channel on which signaling/data/information is transmittedor received, or to the signaling/data/information that is transmitted orreceived on the channel.

It is noted that while aspects may be described herein using terminologycommonly associated with 3G and/or 4G wireless technologies, aspects ofthe present disclosure can be applied in other generation-basedcommunication systems, such as 5G and later.

Example Wireless Communications Network

FIG. 1 illustrates an example wireless communication network 100, inwhich aspects of the present disclosure may be practiced. For example,techniques presented herein may be used for cell CE level determinationin wireless communication network 100, which may be an LTE or laternetwork that includes narrowband Internet-of-things (NB-IoT) and/orenhanced/evolved machine type communications (eMTC) devices. Wirelesscommunication network 100 may include base stations (BSs) 110 and userequipment (UEs) 120. In aspects, a BS 110 can determine at least onenarrowband region of a wideband region for communication with a UE 120.UE 120, which may be a low cost device, such a NB-IoT device or an eMTCUE, can determine the narrowband region and receive, send, monitor, ordecode information on the narrowband region for communication with BS110.

Wireless communication network 100 may be a long term evolution (LTE)network or some other wireless network, such as a new radio (NR) or 5Gnetwork. Wireless communication network 100 may include a number of BSs110 and other network entities. A BS is an entity that communicates withUEs and may also be referred to as a NR BS, a Node B (NB), anevolved/enhanced NB (eNB), a 5G NB, a gNB, an access point (AP), atransmission reception point (TRP), etc. Each BS may providecommunication coverage for a particular geographic area. In 3GPP, theterm “cell” can refer to a coverage area of a BS and/or a BS subsystemserving this coverage area, depending on the context in which the termis used.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). A BS for a macro cell may bereferred to as a macro BS. A BS for a pico cell may be referred to as apico BS. A BS for a femto cell may be referred to as a femto BS or ahome BS. In the example shown in FIG. 1, BS 110 a may be a macro BS fora macro cell 102 a, BS 110 b may be a pico BS for a pico cell 102 b, andBS 110 c may be a femto BS for a femto cell 102 c. A BS may support oneor multiple (e.g., three) cells.

Wireless communication network 100 may also include relay stations. Arelay station is an entity that can receive a transmission of data froman upstream station (e.g., BS 110 or UE 120) and send a transmission ofthe data to a downstream station (e.g., UE 120 or BS 110). A relaystation may also be a UE that can relay transmissions for other UEs. Inthe example shown in FIG. 1, relay station 110 d may communicate withmacro BS 110 a and UE 120 d in order to facilitate communication betweenBS 110 a and UE 120 d. A relay station may also be referred to as arelay BS, a relay, etc.

Wireless communication network 100 may be a heterogeneous network thatincludes BSs of different types, e.g., macro BSs, pico BSs, femto BSs,relay BSs, etc. These different types of BSs may have different transmitpower levels, different coverage areas, and different impact oninterference in wireless communication network 100. For example, macroBSs may have a high transmit power level (e.g., 5 to 40 Watts) whereaspico BSs, femto BSs, and relay BSs may have lower transmit power levels(e.g., 0.1 to 2 Watts).

Network controller 130 may couple to a set of BSs and may providecoordination and control for these BSs. Network controller 130 maycommunicate with the BSs via a backhaul. The BSs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., UE 120 a, UE 120 b, UE 120 c) may be dispersed throughoutwireless communication network 100, and each UE may be stationary ormobile. A UE may also be referred to as an access terminal, a terminal,a mobile station, a subscriber unit, a station, a Customer PremisesEquipment (CPE), etc. A UE may be a cellular phone (e.g., a smartphone), a personal digital assistant (PDA), a wireless modem, a wirelesscommunication device, a handheld device, a laptop computer, a cordlessphone, a wireless local loop (WLL) station, a tablet, a camera, a drone,a robot/robotic device, a netbook, a smartbook, an ultrabook, a medicaldevice, medical equipment, a healthcare device, a biometricsensor/device, a wearable device such as a smart watch, smart clothing,smart glasses, virtual reality goggles, a smart wristband, and/or smartjewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainmentdevice (e.g., a music device, a video device, a gaming device, asatellite radio, etc.), industrial manufacturing equipment, anavigation/positioning device (e.g., GNSS (global navigation satellitesystem) devices based on, for example, GPS (global positioning system),Beidou, GLONASS, Galileo, terrestrial-based devices, etc.), or any othersuitable device configured to communicate via a wireless or wiredmedium. Some UEs may be implemented as IoT (Internet of things) UEs. IoTUEs include, for example, robots/robotic devices, drones, remotedevices, sensors, meters, monitors, cameras, location tags, etc., thatmay communicate with a BS, another device (e.g., remote device), or someother entity. IoT UEs may include MTC/eMTC UEs, NB-IoT UEs, as well asother types of UEs. A wireless node may provide, for example,connectivity for or to a network (e.g., a wide area network such asInternet or a cellular network) via a wired or wireless communicationlink.

One or more UEs 120 in the wireless communication network 100 (e.g., anLTE network) may be a narrowband bandwidth UE. As used herein, deviceswith limited communication resources, e.g. smaller bandwidth, may bereferred to generally as narrowband (NB) UEs or bandwidth limited (BL)UEs. In one example, a limited bandwidth may be 1.4 MHz. In anotherexample, a limited bandwidth may be 5 MHz. Similarly, legacy devices,such as legacy and/or advanced UEs (e.g., in LTE) may be referred togenerally as wideband UEs. Generally, wideband UEs are capable ofoperating on a larger amount of bandwidth than narrowband UEs.

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A dashed line with doublearrows indicates potentially interfering transmissions between a UE anda BS.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular radioaccess technology (RAT) and may operate on one or more frequencies. ARAT may also be referred to as a radio technology, an air interface,etc. A frequency may also be referred to as a carrier, a frequencychannel, etc. Each frequency may support a single RAT in a givengeographic area in order to avoid interference between wireless networksof different RATs. In some cases, NR or 5G RAT networks may be deployed.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a BS 110) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. The scheduling entity may be responsible for scheduling,assigning, reconfiguring, and releasing resources for one or moresubordinate entities. For scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity. BSs 110 are notthe only entities that may function as a scheduling entity. In someexamples, UE 120 may function as a scheduling entity, schedulingresources for one or more subordinate entities (e.g., one or more otherUEs 120). In this example, the UE is functioning as a scheduling entity,and other UEs utilize resources scheduled by the UE for wirelesscommunication. A UE may function as a scheduling entity in apeer-to-peer (P2P) network, and/or in a mesh network. In a mesh networkexample, UEs may optionally communicate directly with one another inaddition to communicating with the scheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

FIG. 2 shows a block diagram of a design of BS 110 and UE 120, which maybe one of the BSs 110 and one of the UEs 120 in FIG. 1. BS 110 may beequipped with Tantennas 234 a through 234 t, and UE 120 may be equippedwith R antennas 252 a through 252 r, where in general T≥1 and R≥1.

At BS 110, transmit processor 220 may receive data from a data source212 for one or more UEs, select one or more modulation and codingschemes (MCS) for each UE based on channel quality indicators (CQIs)received from the UE, process (e.g., encode and modulate) the data foreach UE based on the MCS(s) selected for the UE, and provide datasymbols for all UEs. Transmit processor 220 may also process systeminformation (e.g., for static resource partitioning information (SRPI),etc.) and control information (e.g., CQI requests, grants, upper layersignaling, etc.) and provide overhead symbols and control symbols.Processor 220 may also generate reference symbols for reference signals(e.g., the cell-specific reference signal (CRS)) and synchronizationsignals (e.g., the primary synchronization signal (PSS) and thesecondary synchronization signal (SSS)). Transmit (Tx) multiple-inputmultiple-output (MIMO) processor 230 may perform spatial processing(e.g., precoding) on the data symbols, the control symbols, the overheadsymbols, and/or the reference symbols, if applicable, and may provide Toutput symbol streams to T modulators (MODs) 232 a through 232 t. Eachmodulator 232 may process a respective output symbol stream (e.g., forOFDM, etc.) to obtain an output sample stream. Each modulator 232 mayfurther process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal. Tdownlink signals from modulators 232 a through 232 t may be transmittedvia T antennas 234 a through 234 t, respectively.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other BSs and may provide received signalsto demodulators (DEMODs) 254 a through 254 r, respectively. Eachdemodulator 254 may condition (e.g., filter, amplify, downconvert, anddigitize) its received signal to obtain input samples. Each demodulator254 may further process the input samples (e.g., for OFDM, etc.) toobtain received symbols. MIMO detector 256 may obtain received symbolsfrom all R demodulators 254 a through 254 r, perform MIMO detection onthe received symbols if applicable, and provide detected symbols.Receive processor 258 may process (e.g., demodulate and decode) thedetected symbols, provide decoded data for UE 120 to data sink 260, andprovide decoded control information and system information tocontroller/processor 280. A channel processor may determine referencesignal received power (RSRP), received signal strength indicator (RSSI),reference signal received quality (RSRQ), CQI, etc.

On the uplink, at UE 120, transmit processor 264 may receive and processdata from data source 262 and control information (e.g., for reportscomprising RSRP, RSSI, RSRQ, CQI, etc.) from controller/processor 280.Processor 264 may also generate reference symbols for one or morereference signals. The symbols from transmit processor 264 may beprecoded by Tx MIMO processor 266 if applicable, further processed bymodulators 254 a through 254 r (e.g., for SC-FDM, OFDM, etc.), andtransmitted to BS 110. At BS 110, the uplink signals from UE 120 andother UEs may be received by antennas 234, processed by demodulators232, detected by MIMO detector 236 if applicable, and further processedby receive processor 238 to obtain decoded data and control informationsent by UE 120. Processor 238 may provide the decoded data to data sink239 and the decoded control information to controller/processor 240. BS110 may include communication unit 244 and communicate to networkcontroller 130 via communication unit 244. Network controller 130 mayinclude communication unit 294, controller/processor 290, and memory292.

Controllers/processors 240 and 280 may direct the operation at BS 110and UE 120, respectively, to perform techniques presented herein. Forexample, processor 240 and/or other processors and modules at BS 110,and processor 280 and/or other processors and modules at UE 120, mayperform or direct operations of BS 110 and UE 120, respectively. Forexample, controller/processor 240 and/or other controllers/processorsand modules at BS 110 may perform or direct operations of BS 110. Forexample, controller/processor 280 and/or other controllers/processorsand modules at UE 120 may perform or direct operations 1200 shown inFIG. 12. Memories 242 and 282 may store data and program codes for BS110 and UE 120, respectively. Scheduler 246 may schedule UEs for datatransmission on the downlink and/or uplink.

FIG. 3 shows an exemplary frame structure 300 for frequency divisionduplexing (FDD) in a wireless communication system (e.g., such aswireless communication network 100). The transmission timeline for eachof the downlink and uplink may be partitioned into units of radioframes. Each radio frame may have a predetermined duration (e.g., 10milliseconds (ms)) and may be partitioned into 10 subframes with indicesof 0 through 9. Each subframe may include two slots. Each radio framemay thus include 20 slots with indices of 0 through 19. Each slot mayinclude L symbol periods, for example, seven symbol periods for a normalcyclic prefix (as shown in FIG. 3) or six symbol periods for an extendedcyclic prefix. The 2 L symbol periods in each subframe may be assignedindices of 0 through 2L−1.

In certain wireless communication systems (e.g., LTE), a BS (e.g., suchas a BS 110) may transmit a PSS and a SSS on the downlink in the centerof the system bandwidth for each cell supported by the BS. The PSS andSSS may be transmitted in symbol periods 6 and 5, respectively, insubframes 0 and 5 of each radio frame with the normal cyclic prefix, asshown in FIG. 3. The PSS and SSS may be used by UEs (e.g., such as UEs120) for cell search and acquisition. The BS may transmit a CRS acrossthe system bandwidth for each cell supported by the BS. The CRS may betransmitted in certain symbol periods of each subframe and may be usedby the UEs to perform channel estimation, channel quality measurement,and/or other functions. The BS may also transmit a physical broadcastchannel (PBCH) in symbol periods 0 to 3 in slot 1 of certain radioframes. The PBCH may carry some system information. The BS may transmitother system information such as system information blocks (SIBs) on aphysical downlink shared channel (PDSCH) in certain subframes. The BSmay transmit control information/data on a physical downlink controlchannel (PDCCH) in the first B symbol periods of a subframe, where B maybe configurable for each subframe. The BS may transmit traffic dataand/or other data on the PDSCH in the remaining symbol periods of eachsubframe.

In certain systems (e.g., such as NR or 5G systems), a BS may transmitthese or other signals in these locations or in different locations ofthe subframe.

FIG. 4 shows two exemplary subframe formats 410 and 420 with the normalcyclic prefix. The available time frequency resources may be partitionedinto resource blocks (RBs). Each RB may cover 12 subcarriers in one slotand may include a number of resource elements (REs). Each RE may coverone subcarrier in one symbol period and may be used to send onemodulation symbol, which may be a real or complex value.

Subframe format 410 may be used for two antennas. A CRS may betransmitted from antennas 0 and 1 in symbol periods 0, 4, 7 and 11. Areference signal is a signal that is known a priori by a transmitter anda receiver and may also be referred to as pilot. A CRS is a referencesignal that is specific for a cell, e.g., generated based on a cellidentity (ID). In FIG. 4, for a given RE with label Ra, a modulationsymbol may be transmitted on that RE from antenna a, and no modulationsymbols may be transmitted on that RE from other antennas. Subframeformat 420 may be used with four antennas. A CRS may be transmitted fromAntennas 0 and 1 in symbol periods 0, 4, 7 and 11 and from antennas 2and 3 in symbol periods 1 and 8. For both subframe formats 410 and 420,a CRS may be transmitted on evenly spaced subcarriers, which may bedetermined based on cell ID. CRSs may be transmitted on the same ordifferent subcarriers, depending on their cell IDs. For both subframeformats 410 and 420, REs not used for the CRS may be used to transmitdata (e.g., traffic data, control data, and/or other data).

The PSS, SSS, CRS and PBCH in LTE are described in 3GPP TS 36.211,entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); PhysicalChannels and Modulation,” which is publicly available.

An interlace structure may be used for each of the downlink and uplinkfor FDD in LTE. For example, Q interlaces with indices of 0 through Q−1may be defined, where Q may be equal to 4, 6, 8, 10, or some othervalue. Each interlace may include subframes that are spaced apart by Qframes. In particular, interlace q may include subframes q, q+Q, q+2Q,etc., where q∈{0, . . . ,Q−1}.

The wireless network may support hybrid automatic retransmission request(HARQ) for data transmission on the downlink and uplink. For HARQ, atransmitter (e.g., a BS) may send one or more transmissions of a packetuntil the packet is decoded correctly by a receiver (e.g., a UE) or someother termination condition is encountered. For synchronous HARQ, alltransmissions of the packet may be sent in subframes of a singleinterlace. For asynchronous HARQ, each transmission of the packet may besent in any subframe.

A UE may be located within the coverage of multiple BS. One of these BSsmay be selected to serve the UE. The serving BS may be selected based onvarious criteria such as received signal strength, received signalquality, pathloss, etc. Received signal quality may be quantified by asignal-to-noise-and-interference ratio (SINR), or a RSRQ, or some othermetric. The UE may operate in a dominant interference scenario in whichthe UE may observe high interference from one or more interfering BS.

The wireless communication network may support a 180 kHz deployment fornarrowband operation (e.g., NB-IoT) with different deployment modes. Inone example, narrowband operations may be deployed in-band, for example,using RBs within a wider system bandwidth. In one case, narrowbandoperations may use one RB within the wider system bandwidth of anexisting network (e.g., such as an LTE network). In this case, the 180kHz bandwidth for the RB may have to be aligned with a wideband RB. Inone example, narrowband operations may be deployed in the unused RBswithin a carrier guard-band (e.g., LTE). In this deployment, the 180 kHzRB within the guard band may be aligned with a 15 kHz tone grid ofwideband LTE, for example, in order to use the same Fast FourierTransform (FFT) and/or reduce interference in-band legacy LTEcommunications.

Example Narrowband Communications

The focus of traditional LTE design (e.g., for legacy “non MTC” devices)is on the improvement of spectral efficiency, ubiquitous coverage, andenhanced quality of service (QoS) support. Current LTE system downlink(DL) and uplink (UL) link budgets are designed for coverage of high enddevices, such as state-of-the-art smartphones and tablets, which maysupport a relatively large DL and UL link budget.

However, as described above, one or more UEs in the wirelesscommunication network (e.g., wireless communication network 100) may bedevices that have limited communication resources, such as narrowbandUEs, as compared to other (wideband) devices in the wirelesscommunication network. For narrowband UEs, various requirements may berelaxed as only a limited amount of information may need to beexchanged. For example, maximum bandwidth may be reduced (relative towideband UEs), a single receive radio frequency (RF) chain may be used,peak rate may be reduced (e.g., a maximum of 100 bits for a transportblock size), transmit power may be reduced, Rank 1 transmission may beused, and half duplex operation may be performed.

In some cases, if half-duplex operation is performed, MTC UEs may have arelaxed switching time to transition from transmitting to receiving (orreceiving to transmitting). For example, the switching time may berelaxed from 20 μs for regular UEs to 1 ms for MTC UEs. Release 12 MTCUEs may still monitor downlink (DL) control channels in the same way asregular UEs, for example, monitoring for wideband control channels inthe first few symbols (e.g., PDCCH) as well as narrowband controlchannels occupying a relatively narrowband, but spanning a length of asubframe (e.g., enhanced PDCCH or ePDCCH).

Certain standards (e.g., LTE Release 13) may introduce support forvarious additional MTC enhancements, referred to herein as enhanced MTC(or eMTC). For example, eMTC may provide MTC UEs with coverageenhancements up to 15 dB.

As illustrated in the subframe structure 500 of FIG. 5, eMTC UEs cansupport narrowband operation while operating in a wider system bandwidth(e.g., 1.4/3/5/10/15/20 MHz). In the example illustrated in FIG. 5, aconventional legacy control region 510 may span system bandwidth of afirst few symbols, while a narrowband region 530 of the system bandwidth(spanning a narrow portion of a data region 520) may be reserved for anMTC physical downlink control channel (referred to herein as an M-PDCCH)and for an MTC physical downlink shared channel (referred to herein asan M-PDSCH). In some cases, an MTC UE monitoring the narrowband regionmay operate at 1.4 MHz or 6 resource blocks (RBs).

However, as noted above, eMTC UEs may be able to operate in a cell witha bandwidth larger than 6 RBs. Within this larger bandwidth, each eMTCUE may still operate (e.g., monitor/receive/transmit) while abiding by a6-physical resource block (PRB) constraint. In some cases, differenteMTC UEs may be served by different narrowband regions (e.g., with eachspanning 6-PRB blocks). As the system bandwidth may span from 1.4 to 20MHz, or from 6 to 100 RBs, multiple narrowband regions may exist withinthe larger bandwidth. An eMTC UE may also switch or hop between multiplenarrowband regions in order to reduce interference.

Example Narrowband Internet-of-Things

The Internet-of-Things (IoT) may refer to a network of physical objects,devices, or “things”. IoT devices may be embedded with, for example,electronics, software, or sensors and may have network connectivity,which enable these devices to collect and exchange data. IoT devices maybe sensed and controlled remotely across existing networkinfrastructure, creating opportunities for more direct integrationbetween the physical world and computer-based systems and resulting inimproved efficiency, accuracy, and economic benefit. Systems thatinclude IoT devices augmented with sensors and actuators may be referredto cyber-physical systems. Cyber-physical systems may includetechnologies such as smart grids, smart homes, intelligenttransportation, and/or smart cities. Each “thing” (e.g., IoT device) maybe uniquely identifiable through its embedded computing system may beable to interoperate within existing infrastructure, such as Internetinfrastructure.

NB-IoT may refer to a narrowband (NB) radio technology speciallydesigned for the IoT. NB-IoT may focus on indoor coverage, low cost,long battery life, and large number of devices. To reduce the complexityof UEs, NB-IoT may allow for narrowband deployments utilizing one PRB(e.g., 180 kHz+20 kHz guard band). NB-IoT deployments may utilize higherlayer components of certain systems (e.g., LTE) and hardware to allowfor reduced fragmentation and cross compatibility with, for example,NB-LTE/NB-IoT and/or eMTC.

FIG. 6 illustrates an example deployment 600 of NB-IoT, according tocertain aspects of the present disclosure. Three NB-IoT deploymentconfigurations include in-band, guard-band, and standalone. For thein-band deployment configuration, NB-IoT may coexist with a legacysystem (e.g., GSM, WCDMA, and/or LTE system(s)) deployed in the samefrequency band. For example, the wideband LTE channel may be deployed invarious bandwidths between 1.4 MHz to 20 MHz. As shown in FIG. 6, adedicated RB 602 within that bandwidth may be available for use byNB-IoT and/or the RBs 604 may be dynamically allocated for NB-IoT. Asshown in FIG. 6, in an in-band deployment, one RB, or 200 kHz, of awideband channel (e.g., LTE) may be used for NB-IoT.

Certain systems (e.g., LTE) may include unused portions of the radiospectrum between carriers to guard against interference between adjacentcarriers. In some deployments, NB-IoT may be deployed in a guard band606 of the wideband channel.

In other deployments, NB-IoT may be deployed standalone (not shown). Ina standalone deployment, for example, one 200 MHz carrier may beutilized to carry NB-IoT traffic and GSM spectrum may be reused.

Deployments of NB-IoT may include synchronization signals such as PSSfor frequency and timing synchronization and SSS to convey systeminformation. For NB-IoT operations, PSS/SSS timing boundaries may beextended as compared to the existing PSS/SSS frame boundaries in legacysystems (e.g., LTE), for example, from 10 ms to 40 ms. Based on thetiming boundary, a UE is able to receive a PBCH transmission, which maybe transmitted in subframe 0 of a radio frame.

Example NR/5G RAN Architecture

New radio (NR) may refer to radios configured to operate according to anew air interface (e.g., other than Orthogonal Frequency DivisionalMultiple Access (OFDMA)-based air interfaces) or fixed transport layer(e.g., other than Internet Protocol (IP)). NR may utilize OFDM with a CPon the uplink and downlink and include support for half-duplex operationusing TDD. NR may include Enhanced Mobile Broadband (eMBB) servicetargeting wide bandwidth (e.g. 80 MHz beyond), millimeter wave (mmW)targeting high carrier frequency (e.g. 60 GHz), massive MTC (mMTC)targeting non-backward compatible MTC techniques, and/or missioncritical targeting ultra reliable low latency communications (URLLC)service.

A single component carrier (CC) bandwidth of 100 MHZ may be supported.NR RBs may span 12 sub-carriers with a sub-carrier bandwidth of 75 kHzover a 0.1 ms duration. Each radio frame may consist of 50 subframeswith a length of 10 ms. Consequently, each subframe may have a length of0.2 ms. Each subframe may indicate a link direction (e.g., DL or UL) fordata transmission and the link direction for each subframe may bedynamically switched. Each subframe may include DL/UL data as well asDL/UL control data. UL and DL subframes for NR may be as described inmore detail below with respect to FIGS. 9 and 10.

Beamforming may be supported and beam direction may be dynamicallyconfigured. MIMO transmissions with precoding may also be supported.MIMO configurations in the DL may support up to 8 transmit antennas withmulti-layer DL transmissions up to 8 streams and up to 2 streams per UE.Multi-layer transmissions with up to 2 streams per UE may be supported.Aggregation of multiple cells may be supported with up to 8 servingcells. Alternatively, NR may support a different air interface, otherthan an OFDM-based interface. NR networks may include entities suchcentral units (CUs) or distributed units (DUs).

The NR RAN may include a CU and DUs. A NR BS (e.g., a NB, an eNB, a gNB,a 5G NB, a TRP, an AP, etc.) may correspond to one or multiple BSs. NRcells can be configured as access cells (ACells) or data only cells(DCells). For example, the RAN (e.g., a CU or DU) can configure thecells. DCells may be cells used for carrier aggregation or dualconnectivity, but not used for initial access, cellselection/reselection, or handover. In some cases DCells may nottransmit synchronization signals—in some case cases DCells may transmitsynchronization signals.

FIG. 7 illustrates an example logical architecture 700 of a distributedRAN, according to aspects of the present disclosure. 5G access node 706may include access node controller (ANC) 702. ANC 702 may be a CU of thedistributed RAN. The backhaul interface to the next generation corenetwork (NG-CN) 704 may terminate at ANC 702. The backhaul interface toneighboring next generation access nodes (NG-ANs) 710 may terminate atANC 702. ANC 702 may include one or more TRPs 708. As described above,TRP may be used interchangeably with “cell”, BS, NR BS, NB, eNB, 5G NB,gNB, AP, etc.

TRPs 708 may comprise a DU. TRPs 708 may be connected to one ANC (e.g.,ANC 702) or more than one ANC (not illustrated). For example, for RANsharing, radio as a service (RaaS), and service specific ANDdeployments, TRP 708 may be connected to more than one ANC. TRP 708 mayinclude one or more antenna ports. TRPs 708 may be configured toindividually (e.g., dynamic selection) or jointly (e.g., jointtransmission) serve traffic to a UE.

Logical architecture 700 may be used to illustrate fronthaul definition.The architecture may be defined that support fronthauling solutionsacross different deployment types. For example, logical architecture 700may be based on transmit network capabilities (e.g., bandwidth, latency,and/or jitter). Logical architecture 700 may share features and/orcomponents with LTE. According to aspects, NG-AN 710 may support dualconnectivity with NR. NG-AN 710 may share a common fronthaul for LTE andNR. Logical architecture 700 may enable cooperation between and amongTRPs 708. For example, cooperation may be preset within a TRP and/oracross TRPs via ANC 702. In some cases, no inter-TRP interface may beneeded/present.

A dynamic configuration of split logical functions may be present withinlogical architecture 700. The packet data convergence protocol (PDCP),radio link control (RLC), and medium access control (MAC) protocols maybe adaptably placed at ANC 702 or TRP 708.

FIG. 8 illustrates an example physical architecture 800 of a distributedRAN, according to aspects of the present disclosure. Centralized corenetwork unit (C-CU) 802 may host core network functions. C-CU 802 may becentrally deployed. C-CU 802 functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

Centralized RAN unit (C-RU) 804 may host one or more ANC functions.Optionally, C-RU 804 may host core network functions locally. C-RU 804may have distributed deployment. C-RU 804 may be closer to the networkedge.

DU 806 may host one or more TRPs. DU 806 may be located at edges of thenetwork with radio frequency (RF) functionality.

FIG. 9 is a diagram showing an example of a DL-centric subframe 900,according to aspects of the present disclosure. DL-centric subframe 900may include control portion 902. Control portion 902 may exist in theinitial or beginning portion of DL-centric subframe 900. Control portion902 may include various scheduling information and/or controlinformation corresponding to various portions of DL-centric subframe900. In some configurations, control portion 902 may be a physical DLcontrol channel (PDCCH), as shown in FIG. 9. DL-centric subframe 900 mayalso include DL data portion 904. DL data portion 904 may sometimes bereferred to as the payload of DL-centric subframe 900. DL data portion904 may include the communication resources utilized to communicate DLdata from the scheduling entity (e.g., UE or BS) to the subordinateentity (e.g., UE). In some configurations, DL data portion 904 may be aphysical DL shared channel (PDSCH).

DL-centric subframe 900 may also include common UL portion 906. CommonUL portion 906 may sometimes be referred to as an UL burst, a common ULburst, and/or various other suitable terms. Common UL portion 906 mayinclude feedback information corresponding to various other portions ofDL-centric subframe 900. For example, common UL portion 906 may includefeedback information corresponding to control portion 902. Non-limitingexamples of feedback information may include an acknowledgment (ACK)signal, a negative acknowledgment (NACK) signal, a HARQ indicator,and/or various other suitable types of information. Common UL portion906 may include additional or alternative information, such asinformation pertaining to random access channel (RACH) procedures,scheduling requests (SRs), and various other suitable types ofinformation. As illustrated in FIG. 9, the end of DL data portion 904may be separated in time from the beginning of common UL portion 906.This time separation may sometimes be referred to as a gap, a guardperiod, a guard interval, and/or various other suitable terms. Thisseparation provides time for the switch-over from DL communication(e.g., reception operation by the subordinate entity) to ULcommunication (e.g., transmission by the subordinate entity). One ofordinary skill in the art will understand that the foregoing is merelyone example of a DL-centric subframe and alternative structures havingsimilar features may exist without necessarily deviating from theaspects described herein.

FIG. 10 is a diagram showing an example of an UL-centric subframe 1000,according to aspects of the present disclosure. UL-centric subframe 1000may include control portion 1002. Control portion 1002 may exist in theinitial or beginning portion of UL-centric subframe 1000. Controlportion 1002 in FIG. 10 may be similar to control portion 1002 describedabove with reference to FIG. 9. UL-centric subframe 1000 may alsoinclude UL data portion 1004. UL data portion 1004 may sometimes bereferred to as the payload of UL-centric subframe 1000. The UL portionmay refer to the communication resources utilized to communicate UL datafrom the subordinate entity (e.g., UE) to the scheduling entity (e.g.,UE or BS). In some configurations, control portion 1002 may be a PDCCH.In some configurations, the data portion may be a physical uplink sharedchannel (PUSCH).

As illustrated in FIG. 10, the end of control portion 1002 may beseparated in time from the beginning of UL data portion 1004. This timeseparation may sometimes be referred to as a gap, guard period, guardinterval, and/or various other suitable terms. This separation providestime for the switch-over from DL communication (e.g., receptionoperation by the scheduling entity) to UL communication (e.g.,transmission by the scheduling entity). UL-centric subframe 1000 mayalso include common UL portion 1006. Common UL portion 1006 in FIG. 10may be similar to common UL portion 906 described above with referenceto FIG. 9. Common UL portion 1006 may additionally or alternativelyinclude information pertaining to CQI, sounding reference signals(SRSs), and various other suitable types of information. One of ordinaryskill in the art will understand that the foregoing is merely oneexample of an UL-centric subframe and alternative structures havingsimilar features may exist without necessarily deviating from theaspects described herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UEI) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

A UE may operate in various radio resource configurations, including aconfiguration associated with transmitting pilots using a dedicated setof resources (e.g., a radio resource control (RRC) dedicated state,etc.) or a configuration associated with transmitting pilots using acommon set of resources (e.g., an RRC common state, etc.). Whenoperating in the RRC dedicated state, the UE may select a dedicated setof resources for transmitting a pilot signal to a network. Whenoperating in the RRC common state, the UE may select a common set ofresources for transmitting a pilot signal to the network. In eithercase, a pilot signal transmitted by the UE may be received by one ormore network access devices, such as an AN, a DU, or portions thereof.Each receiving network access device may be configured to receive andmeasure pilot signals transmitted on the common set of resources, andalso receive and measure pilot signals transmitted on dedicated sets ofresources allocated to the UEs for which the network access device is amember of a monitoring set of network access devices for the UE. One ormore of the receiving network access devices, or a CU to which receivingnetwork access device(s) transmit the measurements of the pilot signals,may use the measurements to identify serving cells for the UEs, or toinitiate a change of serving cell for one or more of the UEs.

As mentioned, certain systems (e.g., Release 13 or later eMTC systems),may support narrowband operation. For example, the narrowband operationmay include support for communications on a 6 RB band and half-duplexoperation (e.g., capability to transmit and receive, but not bothsimultaneously) for up to, e.g., 15 dB coverage enhancements. Thesesystems may reserve a portion of the system bandwidth for control, whichmay be an MTC physical downlink control channel (MPDCCH). The MPDCCH maybe transmitted in a narrowband, may use at least one subframe, and mayrely on demodulation reference signal (DMRS) demodulation for decodingof the control channel. Coverage may be increased by performingrepetition/bundling of signals.

Certain systems (e.g., Release 13 or later NB-IoT systems) may supportnarrowband Internet-of-things operation (NB-IOT). NB-IoT may use 180 kHzbandwidth. NB-IoT may offer standalone, in-band, or guard banddeployment scenarios. Standalone deployment may use new bandwidth,whereas guard band deployment may be done using bandwidth typicallyreserved in the guard band of an existing network, such as long termevolution (LTE). In-band deployment on the other hand may use the sameresource blocks in the LTE carrier of the existing LTE network. NB-IoTmay offer increased coverage. NB-IoT may define a new narrowband controlchannel (e.g., Narrowband PDCCH (NPDCCH)), data, and references signalsthat fit in 1 RB.

Example Enhanced NLIC Operation

With increasing numbers of carrier aggregation (CA) bands combinations,self jamming is a prevalent issue in transceivers. Self-jamming may becaused by high power transmission (e.g., up to 23 dBm) leaking into areceiver band in the form of interference, despite isolation between thetransmit (Tx) and receive (Rx) paths. Shrinking die size of the chipcontributes to this issue as this poses a fundamental limitation onhardware resources which may be used to mitigate effects ofself-jamming.

The issue is not limited to single subscriber identity module (SSIM)alone but also has adverse effects on multiple SIM (MSIM) cases (e.g.,LTE+LTE (L+L)) where Tx operating in SUB-1 (subscription-1) can affectthe reception quality of SUB-2 (subscription 2). A subscription refersto the use of a wireless communications network.

NLIC is a method used to mitigate the effects of self-jamming. More andmore band combinations supported in a single transceiver increases thelikelihood of self-jamming and is one the driving forces for using NLIC.Carrier aggregation leads to multiple band combinations that areaffected by self-jamming. Self-jamming may occur for certain frequencyconfigurations: e.g., f_(RX)=3·f_(TX)→3^(rd) harmonic of T_(X) band canleak into the R_(X) band. A close replica of the interference isgenerated using the T_(X) baseband signal and subtracted from thereceived signal. Each CA band combination can potentially be impacted byself jamming, so for each combination a separate mechanism is needed toreject the additional noise by using, e.g., harmonic trap filter. Withincreasing number of CA combinations, it is difficult to have so manyfilters implemented on a, e.g., UE. This is a case where NLIC may beused to cancel interference generated by T_(X) in CA cases. Depending onapplication, NLIC may be implemented based on a number of technologies,including DSP, ASIC, FPGA, special-purpose processors, general-purposeprocessors, etc.

One type of interference addressed by NLIC is harmonic interference,where a single Tx jams the receiver path. For example, in a UE operatingin CA mode with band 17 (B17) and band 4 (B4) combination (e.g., withB17 as primary component carrier (PCC) and B4 as secondary componentcarrier (SCC)), B17 Tx frequency may be 711 MHz and Rx frequency may be741 MHz, and B4 Tx frequency may be 1733 MHz, and Rx frequency may be2133 MHz. Third harmonic of B17 Tx band (3*711=2133 MHz) may leak intothe B4 Rx band, causing interference. NLIC may use the B17 Tx basebandsignal to generate a close replica of the interference so that thereplica is subtracted from the received signal on B4 Rx band.

Another type of interference addressed by NLIC is intermodulationinterference, where jamming occurs due to intermodulation of, e.g., twosimultaneous uplink transmissions. For example, in a UE operating withband 1 (BI) and band 3 (B3), BI Tx frequency may be 1955 MHz and Rxfrequency may be 2145 MHz, and B3 Tx frequency may be 1765 MHz.Intermodulation interference 2*f_(B1TX)−f_(B3TX)(2*1955−1765=2145 MHz)may interfere with the B1 Rx band. NLIC may use the B1 Tx and B3 Txbaseband signals to generate a close replica of the interference so thatthe replica is subtracted from the received signal on B1 Rx band.

To operate NLIC on a certain receiver, it may utilize, for example,dedicated hardware and specific microkernel support. Hence every NLICsupport adds extra hardware components, leading to, e.g., increases incost and die size, additional current consumption (30 mA), etc. On adevice with ‘M’ receivers, there may not be ‘M’ NLIC support to mitigateinterference on all ‘M’ receivers at the same time.

Currently the available or applicable ‘N’ NLIC support may not bearbitrated among the ‘M’ affected carriers/receivers (M>N) in anintelligent fashion to operate the overall system in a more efficientmode (e.g., M and N are integers and their values may vary depending onimplementation, and some examples of the values of M and N,respectively, for illustrative purposes only, may be 16 and 12, 10 and3, 8 and 5, 5 and 3, 3 and 2, etc.).

An enhanced NLIC arbitration scheme is disclosed. It arbitrates amongthe affected receive chains, for example, by taking into account theimportance of each receiver within a subscription or even acrosssubscriptions. A subscription may include a wide area or local areasubscription in licensed or unlicensed spectrum, such as a 3G, 4G (e.g.,LTE), 5G, Wi-Fi, or MulteFire subscription. Also disclosed is mechanismof dynamic NLIC assignment based on changing conditions of differentreceivers in accordance with changing network conditions, scheduling,type of information, etc.

Aspects of this disclosure include efficient utilization of resources(e.g., hardware resources) for optimal performance along with controlledcurrent consumption. Dynamic assignment of NLIC support is provided todifferent receivers based on changing network conditions, scheduling,type of information, etc.

In another aspect, an estimation methodology is performed so that, forexample, the receivers that are affected the most or that are the mostcritical (e.g., due to the type of data carried at a certain time) areprioritized. In one example, overlap between an interferer with the userallocated RBs as a percentage of total RBs allocated in a givenbandwidth is determined. In another example, carriers decoding controlinformation (e.g., physical downlink control channel (PDCCH)) areprioritized over carriers receiving data (e.g., physical downlink sharedchannel (PDSCH)) and NLIC is applied to such prioritized carriers. Inanother example, carriers carrying control information about othercarriers (e.g., in cross carrier scheduling mode) or carrying timinginformation, etc. are prioritized over other carriers and NLIC isapplied to such prioritized carriers.

Techniques for enhanced NLIC operation disclosed herein may be appliedto receivers carrying carriers of the same subscription or receiversassigned to two or more different subscriptions.

Prioritizing and running NLIC on a receiver, for example, may includeprioritizing decoding paging message of a certain subscription ordecoding priority aperiodic SIB (system information block)/MIB (masterinformation block) so that NLIC is applied to a receiver handling thesetypes of messages, because failing to decode these messages because ofinterference would have noticeable adverse impact on the device'sperformance (for example, periodic signals have other opportunities tobe decoded at regular intervals while aperiodic signals do not).

In an aspect, NLIC assignment may be based on RB allocation and actualdegree of overlap between interferer and allocated RBs. For example, incarrier aggregation (CA) mode, there are multiple carriers/receiversaffected by self jamming and need NLIC for interference mitigation. Themost affected carriers/receivers may be identified using criteria suchas: interferer power coupling into receiver chain (e.g., function ofRx-Tx isolation and Tx Power), actual interferer overlap with theallocated RBs (and not the overall carrier bandwidth), and/or receiverconditions of each carrier (e.g., signal quality metrics such as SNR(signal-to-noise ratio)/RSRP (reference signal received power), etc.).Weighted averages or combinations of the aforementioned criteria oradditional criteria may also be used.

For example, FIG. 11 is a diagram illustrating an example NLICassignment scenario based on actual interference overlap with allocatedRBs. In this example, PCC (primary component carrier) has higher overlapwith the Tx interference but there are no allocated RBs in the overlapregion. SCC (secondary component carrier) on the other hand has lesseroverlap with the interference but has allocated RBs in the overlappingregion. Therefore, because of actual interference overlap with theallocated RBs, the device (e.g., UE) assigns NLIC support to SCC and mayre-run this decision-making algorithm or logic every time RB allocationchanges to have dynamic assignment of NLIC to the CC most critical atthat moment.

In as aspect, NLIC assignment may be based on the type of informationcarried by the carriers/receivers or the mode of operation of thecarriers/receivers. With Limited NLIC hardware (N) and number ofimpacted carriers (M) where N<M, currently NLIC hardware is staticallyassigned to carriers but not dynamically allocated based on the type ofdata (e.g., PDSCH vs. PDCCH) carried by them. Therefore, current NLIChardware operates only on the first N impacted carriers even if lattercarriers have higher impact in terms of the information the lattercarriers carry. Higher impact, important, or critical information mayinclude, for example, information that contribute more to a UE'sthroughput, information that has low tolerance for delay, informationthat is related to configuration and control of the UE, etc.

To allocate NLIC hardware to receivers/carriers carrying more importantinformation, NLIC allocation may be dynamically operated byprioritization, for example, prioritizing receivers/carriers carryingcontrol information over data (e.g., PDCCH over PDSCH). Also, a singleNLIC block/hardware block may mitigate interference on all chains on CC(component carrier) in MIMO mode (e.g., because the same or similarinterference may apply to all such chains), therefore carriers operatingin higher order MIMO mode having higher contribution to overall UEthroughput may be prioritized. Furthermore, carriers scheduled/coming upfor gapless measurements may be prioritized over other carriers, becauseif measurements go wrong then potential handover to inferior neighborsmay occur, leading to call drop, RLF (radio link failure), etc.Additionally, carrier/receiver carrying the control information of othercarriers, such as in cross carrier scheduling mode, may be prioritized,since any decode failure could impact multiple carriers.

In an aspect, NLIC assignment and arbitration techniques disclosedherein may be applied across receivers belonging to differentsubscriptions. For example, UEs with L+L (LTE subscription+LTEsubscription) is gaining a lot of traction. Currently NLIC algorithm isevaluated and individually run within the same stack (subscription) butthere are common cases where transmitter of one subscription can causeinterference to the receiver of another subscription.

To enhance NLIC assignment for MSIM (multiple SIM) device with limitedhardware blocks and higher number of affected receivers, decision ofrunning NLIC may be made based on all active transmitters acrosssubscriptions and not only within the same subscription as donecurrently. This technique takes care of cases where transmitter of onesubscription causes interference to the receiver of anothersubscription. In case of dual active mode, voice subscription receiversmay be prioritized over data subscription receivers. Also, receivers ofa subscription handling critical or important information such as pagedecoding, aperiodic SIB/MIB decoding, etc., may be prioritized.Additionally, when critical or important information is about to bedecoded, NLIC may need to be prioritized and assigned to these chainsand be switched back to the original receivers once decoding of thiscritical or important information is done.

According to an aspect of the disclosure, various weighted averages orcombinations of the criteria described herein or additional criteria maybe used to provide enhanced NLIC operation.

FIG. 12 is a flow diagram illustrating example operations 1200 forinterference mitigation, according to aspects described herein.Operations 1200 may be performed, for example, by a device (e.g., UE 120or a portion thereof) supporting a plurality of carriers and NLICoperation. Operations 1200 may begin, at 1202, by receiving signaling onthe plurality of carriers. At 1204, the device dynamically assigns NLICto a subset of the plurality of carriers based on at least one criteria,wherein the NLIC is available to a number of carriers that is less thana total number of carriers in the plurality of carriers. As mentioned ina previous example, on a device with ‘M’ receivers, there may not be ‘M’NLIC support to mitigate interference on all ‘M’ receivers at the sametime. For example, the total number of receivers/carriers may be M, andthe NLIC may be available to only N of the M receivers/carriers at anyone time, where M>N, and where the N receivers/carriers may be anycombination of N receivers/carriers out of the M totalreceivers/carriers.

In an aspect, the at least one criteria is based, at least in part, on alevel of interference detected on a carrier. For example, level ofinterference may comprise a level of power coupling from a transmitterinto a receiver chain (e.g., the level of power coupling comparedagainst a threshold), an overlap of the interference with allocatedresource blocks (RBs) (as illustrated in FIG. 11), receiver signalquality metrics, such as signal-noise-ratio (SNR), reference signalreceived power (RSRP), etc. (e.g., the signal quality metric comparedagainst a threshold), other indicators of level of interference, orcombinations thereof. In one example, a receiver with a higher level ofpower coupling from a transmitter may be prioritized in the NLICassignment over another receiver. In another example, a receiver with alower signal quality metric may be prioritized in the NLIC assignmentover another receiver, and a receiver with a high signal quality metricmay not receive the NLIC assignment.

In another aspect, the at least one criteria is based on a type ofinformation received on or the mode of operation of thecarriers/receivers. For example, the type of information received on theat least one of the plurality of carriers may be control channelinformation, and the device may prioritize assigning the NLIC to the atleast one of the plurality of carriers over a carrier with data channelinformation. Another example of the type of information received on theat least one of the plurality of carriers may be control information forat least one other carrier, such as in a cross-carrier schedulingscenario. For example, the mode of operation of the at least one of theplurality of carriers may be higher order multiple-input multiple-output(MIMO), in which case the at least one of the plurality of carriers maybe prioritized in the NLIC assignment. Another example of the mode ofoperation of the at least one of the plurality of carriers may begapless measurement, in which case the at least one of the plurality ofcarriers may be prioritized in the NLIC assignment.

In another aspect, the device may support a plurality of subscriptions,each subscription comprising at least one carrier and supported by atleast one transmitter and at least one receiver. The at least onecriteria is based, at least in part, on at least one receiver supportingat least one of the plurality of subscriptions. For example, the atleast one criteria may be based on interference from an activetransmitter supporting a subscription of the plurality of subscriptionsto a receiver supporting a different subscription of the plurality ofsubscriptions. In another example, a receiver supporting a subscriptionwith active voice communications is prioritized in the NLIC assignmentover a receiver supporting a subscription with active datacommunications. In another example, a receiver supporting a subscriptionwith critical information comprising at least one of page decodinginformation, aperiodic system information block (SIB), or aperiodicmaster information block (MIB), is prioritized in the NLIC assignmentover a receiver supporting another subscription. When criticalinformation is about to be decoded, the device may switch the NLICassignment from a receiver to the receiver with the critical informationbefore decoding the critical information and switch the NLIC assignmentback after the decoding of the critical information. An example of theplurality of subscriptions comprise long term evolution (LTE)subscriptions (e.g., LTE+LTE).

In an aspect, the at least one criteria comprises a weighted average ora combination of two or more aforementioned criteria or additionalcriteria.

As support for higher and higher order CA and support for more and morereceivers increase, intelligent assignment of limited NLIC hardware tomost critical or important receivers based on multiple criteria, asdisclosed herein, would provide significant and noticeable performancegains.

As used herein, the term “identifying” encompasses a wide variety ofactions. For example, “identifying” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “identifying” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“identifying” may include resolving, selecting, choosing, establishingand the like.

Moreover, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or.” That is, unless specified otherwise, or clearfrom the context, the phrase, for example, “X employs A or B” isintended to mean any of the natural inclusive permutations. That is, forexample the phrase “X employs A or B” is satisfied by any of thefollowing instances: X employs A; X employs B; or X employs both A andB. As used herein, reference to an element in the singular is notintended to mean “one and only one” unless specifically so stated, butrather “one or more.” For example, the articles “a” and “an” as used inthis application and the appended claims should generally be construedto mean “one or more” unless specified otherwise or clear from thecontext to be directed to a singular form. Unless specifically statedotherwise, the term “some” refers to one or more. A phrase referring to“at least one of” a list of items refers to any combination of thoseitems, including single members. As an example, “at least one of: a, b,or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c, as wellas any combination with multiples of the same element (e.g., a-a, a-a-a,a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or anyother ordering of a, b, and c). As used herein, including in the claims,the term “and/or,” when used in a list of two or more items, means thatany one of the listed items can be employed by itself, or anycombination of two or more of the listed items can be employed. Forexample, if a composition is described as containing components A, B,and/or C, the composition can contain A alone; B alone; C alone; A and Bin combination; A and C in combination; B and C in combination; or A, B,and C in combination.

In some cases, rather than actually communicating a frame, a device mayhave an interface to communicate a frame for transmission or reception.For example, a processor may output a frame, via a bus interface, to anRF front end for transmission. Similarly, rather than actually receivinga frame, a device may have an interface to obtain a frame received fromanother device. For example, a processor may obtain (or receive) aframe, via a bus interface, from an RF front end for transmission.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in Figures, those operations maybe performed by any suitable corresponding counterpartmeans-plus-function components.

For example, means for assigning, means for prioritizing, means forswitching, means for decoding, means for determining, means foridentifying; means for attempting, means for measuring, means forstarting, means for selecting, means for transmitting, means forreceiving, means for sending, means for comparing, means for increasing,and/or means for decreasing may include one or more processors,transmitters, receivers, antennas, and/or other elements of the userequipment 120 and/or the base station 110 illustrated in FIG. 2.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or combinations thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as hardware,software, or combinations thereof. To clearly illustrate thisinterchangeability of hardware and software, various illustrativecomponents, blocks, modules, circuits, and steps have been describedabove generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the NLIC functions described herein. One ormore aforementioned devices or processors may execute software. Softwareshall be construed broadly to mean instructions, instruction sets, code,code segments, program code, programs, subprograms, software modules,applications, software applications, software packages, routines,subroutines, objects, executables, threads of execution, procedures,functions, etc., whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination thereof. A softwaremodule may reside in RAM memory, flash memory, ROM memory, EPROM memory,EEPROM memory, phase change memory, registers, hard disk, a removabledisk, a CD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, or combinations thereof. Ifimplemented in software, the functions may be stored on or transmittedover as one or more instructions or code on a computer-readable medium.Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage media may be anyavailable media that can be accessed by a general-purpose orspecial-purpose computer or processor. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD/DVD or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-Ray®disc where disks usually reproduce data magnetically, while discsreproduce data optically with lasers. Combinations of the above shouldalso be included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for interference mitigation by a userequipment (UE) comprising a plurality of non-linear interferencecancellation (NLIC) hardware blocks, comprising: receiving signaling ona plurality of carriers; and dynamically assigning based on at least onecriteria the plurality of NLIC hardware blocks, without networkassistance, to a number of the plurality of carriers, wherein the numbervaries over time, wherein a total number of the plurality of NLIChardware blocks is only available to a number of carriers that is lessthan a total number of carriers in the plurality of carriers.
 2. Themethod of claim 1, wherein the at least one criteria is based, at leastin part, on a level of interference detected on a carrier.
 3. The methodof claim 2, wherein the level of interference comprises a level of powercoupling from a transmitter into a receiver chain.
 4. The method ofclaim 2, wherein the level of interference comprises an overlap of theinterference with allocated resource blocks (RBs).
 5. The method ofclaim 2, wherein the level of interference comprises signal-noise-ratio(SNR) or reference signal received power (RSRP).
 6. The method of claim1, wherein the at least one criteria is based, at least in part, on atype of information received on or a mode of operation of at least oneof the plurality of carriers.
 7. The method of claim 6, wherein the typeof information received on the at least one of the plurality of carriersis control channel information, further comprising prioritizing theassigning of the at least one of the plurality of carriers over acarrier with data channel information.
 8. The method of claim 6, whereinthe mode of operation of the at least one of the plurality of carriersis higher order multiple-input multiple-output (MIMO).
 9. The method ofclaim 6, wherein the mode of operation of the at least one of theplurality of carriers is gapless measurement.
 10. The method of claim 6,wherein the type of information received on the at least one of theplurality of carriers is control information for at least one othercarrier.
 11. The method of claim 1, wherein the UE supports a pluralityof subscriptions, each subscription comprising at least one carrier andsupported by at least one transmitter and at least one receiver, andwherein the at least one criteria is based, at least in part, on atleast one receiver supporting at least one of the plurality ofsubscriptions.
 12. The method of claim 11, wherein the at least onecriteria is based on interference from an active transmitter supportinga subscription of the plurality of subscriptions to a receiversupporting a different subscription of the plurality of subscriptions.13. The method of claim 11, wherein a receiver supporting a subscriptionwith active voice communications is prioritized in the assigning over areceiver supporting a subscription with active data communications. 14.The method of claim 11, wherein a receiver supporting a subscriptionwith critical information comprising at least one of page decodinginformation, aperiodic system information block (SIB), or aperiodicmaster information block (MIB), is prioritized in the assigning over areceiver supporting another subscription.
 15. The method of claim 14,further comprising: switching the assignment from a receiver to thereceiver with the critical information before decoding the criticalinformation; and switching the assignment back after the decoding of thecritical information.
 16. The method of claim 11, wherein the pluralityof subscriptions comprise long term evolution (LTE) subscriptions. 17.The method of claim 1, wherein the at least one criteria comprises aweighted average of at least two criteria.
 18. A apparatus forinterference mitigation by a user equipment (UE) comprising a pluralityof non-linear interference cancellation (NLIC) hardware blocks,comprising: at least one processor; memory coupled to the at least oneprocessor, the memory comprising code executable by the at least oneprocessor to cause the UE to: receive signaling on a plurality ofcarriers; and dynamically assign based on at least one criteria theplurality of NLIC hardware blocks, without network assistance, to anumber of the plurality of carriers, wherein the number varies overtime, wherein a total number of the plurality of NLIC hardware blocks isonly available to a number of carriers that is less than a total numberof carriers in the plurality of carriers.
 19. The apparatus of claim 18,wherein the at least one criteria is based, at least in part, on a levelof interference detected on a carrier.
 20. The apparatus of claim 19,wherein the level of interference comprises at least one of: a level ofpower coupling from a transmitter into a receiver chain; an overlap ofthe interference with allocated resource blocks (RBs); orsignal-noise-ratio (SNR) or reference signal received power (RSRP). 21.The apparatus of claim 18, wherein the at least one criteria is based,at least in part, on a type of information received on or a mode ofoperation of at least one of the plurality of carriers.
 22. Theapparatus of claim 21, wherein the type of information received on theat least one of the plurality of carriers comprises at least one of:control information for the same carrier or control information for atleast one other carrier.
 23. The apparatus of claim 21, wherein the modeof operation of the at least one of the plurality of carriers compriseat least one of: higher order multiple-input multiple-output (MIMO) orgapless measurement.
 24. The apparatus of claim 18, wherein the UEsupports a plurality of subscriptions, each subscription comprising atleast one carrier and supported by a transmitter and a receiver, andwherein the at least one criteria is based, at least in part, onreceivers corresponding to the plurality of subscriptions.
 25. Theapparatus of claim 24, wherein the at least one criteria is based oninterference from an active transmitter supporting a subscription of theplurality of subscriptions to a receiver supporting a differentsubscription of the plurality of subscriptions.
 26. The apparatus ofclaim 24, wherein a receiver supporting a subscription with active voicecommunications is prioritized in the assigning over a receiversupporting a subscription with active data communications.
 27. Theapparatus of claim 24, wherein a receiver supporting a subscription withcritical information comprising at least one of page decodinginformation, aperiodic system information block (SIB), or aperiodicmaster information block (MIB), is prioritized in the assigning over areceiver supporting another subscription.
 28. The apparatus of claim 27,wherein the memory further comprises code executable by the at least oneprocessor to cause the UE to: switch the assignment from a receiver tothe receiver with the critical information before decoding the criticalinformation; and switch the assignment back after the decoding of thecritical information.
 29. An apparatus for interference mitigation by auser equipment (UE) comprising a plurality of non-linear interferencecancellation (NLIC) hardware blocks, comprising: means for receivingsignaling on a plurality of carriers; and means for dynamicallyassigning based on at least one criteria the plurality of NLIC hardwareblocks, without network assistance, to a number of the plurality ofcarriers, wherein the number varies over time, wherein a total number ofthe plurality of NLIC hardware blocks is only available to a number ofcarriers that is less than a total number of carriers in the pluralityof carriers.
 30. A non-transitory storage medium for interferencemitigation by a user equipment (UE) comprising a plurality of non-linearinterference cancellation (NLIC) hardware blocks, the non-transitorystorage medium comprising: code to receive signaling on a plurality ofcarriers; and code to dynamically assign based on at least one criteriathe plurality of NLIC hardware blocks, without network assistance, to anumber of the plurality of carriers, wherein the number varies overtime, wherein a total number of the plurality of NLIC hardware blocks isonly available to a number of carriers that is less than a total numberof carriers in the plurality of carriers.